U.S. patent number 10,126,568 [Application Number 15/128,748] was granted by the patent office on 2018-11-13 for multifocal ophthalmic spectacle lens arranged to output a supplementary image.
This patent grant is currently assigned to Essilor International. The grantee listed for this patent is Essilor International. Invention is credited to Sebastien Fricker, Benjamin Rousseau.
United States Patent |
10,126,568 |
Rousseau , et al. |
November 13, 2018 |
Multifocal ophthalmic spectacle lens arranged to output a
supplementary image
Abstract
A multifocal ophthalmic spectacle lens (10) capable of
correcting a wearer's ophthalmic vision and having a back surface
(BS) and a front surface (FS), said lens comprising a light guide
optical element arranged to output a supplementary image (SI) to
the wearer through an exit surface (ES) of said light guide optical
element, where the exit surface (ES), the back surface (BS) and an
optical material located between said exit surface (ES) and said
back surface (BS) form an optical device (OD) and wherein said
optical device (OD) comprises an area of stabilized optical
power.
Inventors: |
Rousseau; Benjamin (Charenton
le Pont, FR), Fricker; Sebastien (Charenton le Pont,
FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Essilor International |
Charenton le Pont |
N/A |
FR |
|
|
Assignee: |
Essilor International
(Charenton le Pont, FR)
|
Family
ID: |
50513846 |
Appl.
No.: |
15/128,748 |
Filed: |
March 27, 2015 |
PCT
Filed: |
March 27, 2015 |
PCT No.: |
PCT/EP2015/056751 |
371(c)(1),(2),(4) Date: |
September 23, 2016 |
PCT
Pub. No.: |
WO2015/150269 |
PCT
Pub. Date: |
October 08, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170351117 A1 |
Dec 7, 2017 |
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Foreign Application Priority Data
|
|
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|
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Apr 1, 2014 [EP] |
|
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14290091 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02C
7/068 (20130101); G02C 7/027 (20130101); G02B
6/0011 (20130101); G02C 7/086 (20130101); G02C
7/028 (20130101); G02B 27/0172 (20130101); G02B
2027/0178 (20130101) |
Current International
Class: |
G02C
7/00 (20060101); G02C 7/02 (20060101); G02C
7/06 (20060101); G02B 27/01 (20060101); F21V
8/00 (20060101) |
Field of
Search: |
;351/41,159.01,159.41,159.42 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2 492 740 |
|
Aug 2012 |
|
EP |
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WO 01/25837 |
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Apr 2001 |
|
WO |
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WO 2001/95027 |
|
Dec 2001 |
|
WO |
|
WO 2005/024491 |
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Mar 2005 |
|
WO |
|
WO 2007/017766 |
|
Feb 2007 |
|
WO |
|
WO 2008/090000 |
|
Jul 2008 |
|
WO |
|
Other References
P Allione, F. Ahsbahs and G. Le Saux, "Application of Optimization
in Computer-Aided Ophthalmic lens design", in SPIE vol. 3737,
EUROPTO Conference on Design and Engineering of Optical Systems,
Berlin, May 1999). cited by applicant.
|
Primary Examiner: Tra; Tuyen
Attorney, Agent or Firm: Oblon, McClelland, Maier &
Neustadt, L.L.P.
Claims
The invention claimed is:
1. A multifocal ophthalmic spectacle lens to correct a wearer's
ophthalmic vision and comprising: a back surface and a front
surface, where the back surface is positioned closest to a wearer's
eye when the multifocal ophthalmic spectacle lens is worn, a light
guide optical element arranged to output a supplementary image to
the wearer through an exit surface of said light guide optical
element, where the exit surface, the back surface, and an optical
material located between said exit surface and said back surface
form an optical device, wherein said optical device comprises an
area of stabilized optical power; and wherein the exit surface is
defined by an angular aperture contour, denoted AC(.alpha.,.beta.),
.alpha. being the eye declination angle and .beta. being the eye
azimuth angle, wherein the angular aperture contour,
AC(.alpha.,.beta.), is situated in the area of stabilized optical
power where the optical device fulfils the requirement of following
equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1) where P(.alpha.,.beta.) is the dioptric power of the optical
device and P.sub.mean is the mean dioptric power of the optical
device within the contour AC(.alpha.,.beta.), wherein
P(.alpha.,.beta.) and P.sub.mean are expressed in Diopter.
2. The multifocal ophthalmic spectacle lens as claimed in claim 1,
according to which the .alpha. variation range within
AC(.alpha.,.beta.) and the .beta. variation range within
AC(.alpha.,.beta.) are each equal or greater to 5.degree..
3. The multifocal ophthalmic spectacle lens as claimed in claim 1,
according to which the optical device is located in an area of
stabilized astigmatism, wherein the exit surface is defined by an
angular aperture contour, denoted AC(.alpha.,.beta.), .alpha. being
the eye declination angle and .beta. being the eye azimuth angle,
wherein the angular aperture contour, AC (.alpha.,.beta.) is
situated in the area of stabilized astigmatism so that the optical
device fulfils the requirement of following equation (E2) when
(.alpha.,.beta.) is within the contour AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter; (E2):
where UnAsti(.alpha.,.beta.) is the unwanted astigmatism value of
the optical device and wherein UnAsti is expressed in Diopter.
4. The multifocal ophthalmic spectacle lens as claimed in claim 1,
according to which the area of stabilized optical power results
from the optical power generated by the geometry of the back
surface.
5. The multifocal ophthalmic spectacle lens as claimed in claim 1,
according to which the multifocal ophthalmic spectacle lens is a
progressive addition spectacle lens chosen within the list
consisting of a spectacle lens comprising a far vision zone, an
intermediate vision zone and a near vision zone; a spectacle lens
comprising an intermediate vision zone and a near vision zone; a
spectacle lens comprising a far vision zone and an intermediate
vision zone.
6. The multifocal ophthalmic spectacle lens as claimed in claim 5,
according to which the multifocal ophthalmic spectacle lens is a
spectacle lens comprising a far vision zone, an intermediate vision
zone and a near vision zone or a spectacle lens comprising, a far
vision zone and an intermediate vision zone, where the back surface
is a progressive surface or a regressive surface and where the
angular aperture contour, AC(.alpha.,.beta.), is located in the far
vision zone.
7. The multifocal ophthalmic spectacle lens as claimed in claim 5,
according to which the multifocal ophthalmic spectacle lens is a
spectacle lens comprising a far vision zone, an intermediate vision
zone and a near vision zone or a spectacle lens comprising an
intermediate vision zone and a near vision zone, where the back
surface is a progressive surface or a regressive surface, and where
the angular aperture contour, AC(.alpha.,.beta.), is located in the
near vision zone.
8. The multifocal ophthalmic spectacle lens as claimed in claim 5,
according to which the back surface is a progressive surface or a
regressive surface, and where the angular aperture contour,
AC(.alpha.,.beta.), is located in the temporal zone or in the nasal
zone of the spectacle lens, in a zone where a meets the
intermediate vision zone.
9. The multifocal ophthalmic spectacle lens as claimed in claim 5,
according to which the front surface is a progressive surface and
the back surface is a surface where the absolute value of the mean
sphere value differences over said surface are equal to or less
than 0.5 Diopter.
10. The multifocal ophthalmic spectacle lens as claimed in claim 5,
according to which the back surface is a progressive surface or a
regressive surface, and where the angular aperture contour,
AC(.alpha.,.beta.), is located in a part of the intermediate vision
zone where the absolute values of the mean sphere value differences
over said part of the intermediate vision zone are equal to or less
than 0.5 Diopter.
11. The multifocal ophthalmic spectacle lens as claimed in claim 5,
according to which the back surface is a progressive surface and
comprising a surface discontinuity located around the angular
aperture contour, AC(.alpha.,.beta.).
12. The multifocal ophthalmic spectacle lens as claimed in claim 1,
according to which the multifocal ophthalmic spectacle lens is
chosen within the list consisting of bifocal lens and trifocal
lens.
13. A method for calculating with a computer a multifocal
ophthalmic spectacle lens to correct wearer's vision, the method
comprising: providing the multifocal ophthalmic spectacle lens
having a back surface and a front surface where the back surface is
positioned closest to a wearer's eye when the multifocal ophthalmic
spectacle lens is worn, the multifocal ophthalmic spectacle lens
comprising a light guide optical element arranged to output a
supplementary image to the wearer through an exit surface of said
light guide optical element, where the exit surface, the back
surface and an optical material located between said exit surface
and said back surface form an optical device so that said optical
device is located in an area of stabilized optical power, and
calculating the geometry of the back surface and the geometry of
the front surface using an optimization method involving a target
lens that has a virtual optical function according to a wearer's
prescription, wherein the exit surface is defined by an angular
aperture contour, denoted AC(.alpha.,.beta.), .alpha. being the eye
declination angle and .beta. being the eye azimuth angle, and
wherein the angular aperture contour, AC(.alpha.,.beta.), is
situated in the area of stabilized optical power where the optical
device fulfils the requirement of following equation (E1) when
(.alpha.,.beta.) is within the contour AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1): where P(.alpha.,.beta.) is the dioptric power of the optical
device and P.sub.mean is the mean dioptric power of the optical
device within the contour AC(.alpha.,.beta.), wherein
P(.alpha.,.beta.) and P.sub.mean are expressed in Diopter.
Description
RELATED APPLICATIONS
This is a U.S. national stage application under 35 USC .sctn. 371
of International application No. PCT/EP2015/056751 filed on Mar.
27, 2015. This application claims the priority of European
application no. 14290091.9 filed Apr. 1, 2014, the entire content
of which is hereby incorporated by reference.
FIELD OF THE INVENTION
The invention relates generally to the field of multifocal
ophthalmic spectacle lenses. More specifically, it relates to a
multifocal ophthalmic spectacle lens capable of correcting wearer's
ophthalmic vision and comprising a light guide optical element
arranged to output a supplementary image to the wearer.
BACKGROUND OF THE INVENTION
Ophthalmic spectacle lenses providing an ophthalmic vision and a
supplementary vision are known in the prior art. Said ophthalmic
spectacle lenses have a front face and a back face and comprise a
light-guide optical element. Said light-guide optical element is a
device designed to transport light from a light source (for example
light beam generator system) to the wearer's eye to enable
information content to be viewed with minimal loss of information.
According to an embodiment, light beams are reflected a plurality
of times between two "reflection" faces between being introduced
into the spectacle lens and exiting therefrom, said two reflection
faces being faces of the light-guide optical element.
SUMMARY OF THE INVENTION
One object of the invention is to provide a multifocal ophthalmic
spectacle lens providing both a suitable ophthalmic vision and a
suitable supplementary vision so that the viewer sees both images
clearly.
For this purpose, an aspect of the invention is directed to a
multifocal ophthalmic lens capable of correcting a wearer's
ophthalmic vision and having a back surface and a front surface,
where the back surface is positioned closest to a wearer's eye when
the multifocal ophthalmic lens is worn, the multifocal ophthalmic
lens comprising a light guide optical element arranged to output a
supplementary image to the wearer through an exit surface of said
light guide optical element, where the exit surface, the back
surface and an optical material located between said exit surface
and said back surface form an optical device and wherein said
optical device comprises an area of stabilized optical power, and
wherein the exit surface is defined by an angular aperture contour,
denoted AC(.alpha.,.beta.), .alpha. being the eye declination angle
and .beta. being the eye azimuth angle, wherein the angular
aperture contour, AC(.alpha.,.beta.), is situated in the area of
stabilized optical power so that the optical device fulfils the
requirement of following equation (E1) when (.alpha.,.beta.) is
within the contour AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
where P(.alpha.,.beta.) is the dioptric power of the optical device
and P.sub.mean is the mean dioptric power of the optical device
within the contour AC(.alpha.,.beta.), wherein P(.alpha.,.beta.)
and P.sub.mean are expressed in Diopter.
In the context of the present invention, the expression "area of
stabilized optical power" refers to an area where the wearer can
see clearly in all gaze directions without changing its
accommodation. An area of stabilized optical power is an area where
the requirements of the following equation are fulfilled: -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
Thanks to a multifocal ophthalmic lens according to the present
invention, a wearer can comfortably see a scene and/or look to a
supplementary image.
In the context of the present invention, the expression "ophthalmic
vision" means the visible perception of a scene such that this
scene appears to him in front of him. Image of the scene originates
directly from the wearer's environment when viewing said scene. The
global information which is contained in the scene is thus
perceived even though the image of the scene is deformed to provide
a corrected image according to wearer's prescription.
Unlike the ophthalmic vision, a supplementary vision may provide
the subject with information that does not originate directly from
his environment. It may be data presented to the subject. For
example, navigation data which are projected overlaid on the visor
of an airplane pilot's headset constitute a supplementary vision,
of the informative vision type. A supplementary vision of another
type may supply modified images of certain parts of the subject's
environment. Thus, other examples of supplementary vision are the
provision of an infrared image which is converted into visible
light, or an image of a part of the subject's environment which is
enlarged.
A spectacle lens to which the invention is applied is designed to
present such supplementary images in the field of vision of the
wearer, or in a part of this field, while retaining the ophthalmic
vision. In other words, the two visions, ophthalmic and
supplementary, are available to the wearer. They may be available
simultaneously or alternately. In the case of an informative
supplementary vision, the supplementary image corresponds to the
visual presentation of information data. These data may appear
overlaid on the ophthalmic image, notably with a light intensity
which is greater or with a color which is distinct. The ophthalmic
image may remain visible or not while the data of the informative
supplementary vision are presented to the wearer.
In the context of the present invention, the expression "optical
device" is a subpart of an ophthalmic spectacle lens. An optical
device is defined by two surfaces and by the optical material
located between said surfaces, namely by its refractive index.
"Multifocal lens" are designed to provide two or more portions of
different focal powers; the focal power change may be discontinuous
or may be continuous over a part or over the whole of the lens.
Among multifocal lenses, one can find bifocal lenses, trifocal
lenses, and progressive-addition lenses.
A bifocal lens is a multifocal lens having two portions, usually
for far and near vision; the focal power change is then
discontinuous.
A trifocal lens is a multifocal lens having three portions, usually
for far, intermediate and near vision; the focal power changes are
then discontinuous.
A progressive-power lens or progressive-addition lens is a lens
with a positive dioptric add power.
By "progressive addition surface" is meant a continuous, aspheric
surface having at least two distance vision zones and a zone
connecting said two distance vision zones, where the dioptric power
in the connecting zone increases between the farthest distance
vision zone (remote vision zone) and the nearest distance vision
zone (closer vision zone).
By "regressive surface" is meant a continuous, aspheric surface
having at least two distance vision zones and a zone connecting
said two distance vision zones, where the dioptric power in the
connecting zone decreases between the farthest distance vision zone
and the nearest distance vision zone.
By "distance vision zone" is meant a zone of the multifocal lens
where the viewer has a comfortable vision for a given distance;
distance vision zones are usually chosen within the list consisting
of far vision zone (far viewing distance, namely viewing distance
of more than four meters), intermediate vision zone (medium
distance such as computer viewing distance, namely viewing distance
of about 60 cm to four meters), near vision zone (reading distance,
namely viewing distance of less than 60 cm).
By "dioptric add power" is meant the amount of dioptric power
difference between two distance vision zones where said difference
is calculated between the dioptric power of the nearest distance
vision zone and the dioptric power of the farthest distance vision
zone.
According to different embodiments of the present invention, that
may be combined according to all technically valuable embodiments:
the .alpha. variation range within AC(.alpha.,.beta.) and the
.beta. variation range within AC(.alpha.,.beta.) are each equal or
greater to 5.degree. (degree); according to an embodiment of
preceding feature, the .alpha. variation range within
AC(.alpha.,.beta.) and/or the .beta. variation range within
AC(.alpha.,.beta.) is (are) equal or greater to 15.degree.;
according to a further embodiment, the .alpha. variation range
within AC(.alpha.,.beta.) and/or the .beta. variation range within
AC(.alpha.,.beta.) is (are) equal or greater to 30.degree.; the
optical device is located in an area of stabilized astigmatism; in
the context of the present invention, the expression "area of
stabilized astigmatism" refers to an area where the norm of the
astigmatism of the optical device is relatively uniform. According
to an embodiment, an area of stabilized astigmatism is a zone where
the requirements of following equation are fulfilled: -0.5
Diopter.ltoreq.Asti(.alpha.,.beta.)-Asti.sub.mean.ltoreq.0.5
Diopter; Asti(.alpha.,.beta.) being the norm of the astigmatism in
the .alpha.,.beta. gaze direction and Asti.sub.mean being the mean
of the astigmatism norm over said area, wherein
Asti(.alpha.,.beta.) and Asti.sub.mean are expressed in Diopter;
the exit surface is defined by an angular aperture contour, denoted
AC(.alpha.,.beta.), .alpha. being the eye declination angle and
.beta. being the eye azimuth angle, wherein the angular aperture
contour, AC(.alpha.,.beta.), is situated in the area of stabilized
astigmatism so that the optical device fulfils the requirement of
following equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter; (E2):
where UnAsti(.alpha.,.beta.) is the norm of the unwanted
astigmatism of the optical device and wherein UnAsti is expressed
in Diopter; the area of stabilized optical power results from the
optical power generated by the geometry of the back surface
(BS).
According to the present invention, the unwanted astigmatism,
UnAsti(.alpha.,.beta.), is the astigmatism vectorial difference
between the astigmatism suitable for correcting the wearer's
ophthalmic vision, i.e. the astigmatism of the wearer's
prescription, and the actual astigmatism of the optical device. The
term `unwanted astigmatism` is used to denote the data pair formed
by an amplitude value and a value of angle. Although this is an
abuse of language, it is also sometimes used to denote the
amplitude of the unwanted astigmatism only.
According to an embodiment of the present invention, the multifocal
ophthalmic lens is a progressive addition lens chosen within the
list consisting of a lens comprising a far vision zone, an
intermediate vision zone and a near vision zone; a lens comprising
an intermediate vision zone and a near vision zone; a lens
comprising a far vision zone and an intermediate vision zone.
Progressive addition ophthalmic lenses are now well known. Such
lenses are used to compensate for presbyopia and allow the
spectacle wearer to see objects over a wide range of distances,
without having to remove his or her glasses. Progressive addition
lenses typically, but not limited to, have a remote vision region,
located in the top of the lens, a closer vision region located in
the bottom of the lens.
According to the wearer's needs, a progressive addition ophthalmic
lens encompasses different embodiments such as followings: the
remote vision is the far vision and the closer vision is the near
vision; the remote vision is the intermediate vision and the closer
vision is the near vision; the remote vision is the far vision and
the closer vision is the intermediate vision.
A prescription for a given presbyopic wearer comprises a prescribed
power value for remote vision and a prescribed power addition
representative of the power increment needed between remote vision
and closer vision. The power addition is termed the "prescribed
addition".
One usually considers that a wearer is presbyopic when the
prescribed addition is more than 0.5 Diopter, preferably equal or
greater than 0.75 Diopter.
Accordingly a person skilled in the art would consider that an
ophthalmic lens is a progressive addition lens only if the power
variation observed on the lens is at least 0.5 Diopter, and
preferably equal or greater than 0.75 Diopter.
According to preceding embodiment, the present invention may be
directed to following additional but alternative features: the
multifocal ophthalmic lens is a progressive addition lens
comprising a far vision zone, an intermediate vision zone and a
near vision zone or a lens comprising a far vision zone and an
intermediate vision zone, where the back surface is a progressive
surface or a regressive surface and where the angular aperture
contour, AC(.alpha.,.beta.), is located in the far vision zone; the
multifocal ophthalmic lens is a progressive addition lens
comprising a far vision zone, an intermediate vision zone and a
near vision zone or a lens comprising an intermediate vision zone
and a near vision zone, where the back surface is a progressive
surface or a regressive surface, and where the angular aperture
contour, AC(.alpha.,.beta.), is located in the near vision zone;
the back surface is a progressive surface or a regressive surface,
and where the angular aperture contour, AC(.alpha.,.beta.), is
located in the temporal zone or in the nasal zone of the lens, in a
zone where a meets the intermediate vision zone; the front surface
is a progressive surface and the back surface is a surface where
the absolute values of the mean sphere value differences over said
surface are equal or less to 0.5 Diopter; the back surface is a
progressive surface or a regressive surface, and where the angular
aperture contour, AC(.alpha.,.beta.), is located in a part of the
intermediate vision zone where the absolute value of the mean
sphere value differences over said part of the intermediate vision
zone are equal or less to 0.5 Diopter; the back surface is a
progressive surface comprising a surface discontinuity located
around the angular aperture contour, AC(.alpha.,.beta.).
According to an embodiment of the present invention, the multifocal
ophthalmic lens is chosen within the list consisting of bifocal
lens and trifocal lens.
According to preceding embodiment the bifocal lens is a lens chosen
within the list consisting of a lens comprising an intermediate
vision zone and a near vision zone; a lens comprising a far vision
zone and an intermediate vision zone; a lens comprising a far
vision zone and a near vision zone.
According an embodiment, the trifocal lens is a lens comprising a
far vision zone, an intermediate vision zone and a near vision
zone.
Another aspect of the present invention is directed to a method for
calculating with computer means a multifocal ophthalmic lens
capable of correcting wearer's ophthalmic vision and having a back
surface and a front surface, where the back surface is positioned
closest to a wearer's eye when the multifocal ophthalmic lens is
worn, the multifocal ophthalmic lens comprising a light guide
optical element arranged to output a supplementary image to the
wearer through an exit surface of said light-conducting element,
where the exit surface, the back surface and an optical material
located between said exit surface and said back surface form an
optical device so that said optical device is located in an area of
stabilized optical power.
According to an embodiment, the geometry of the back surface and
the geometry of the front surface are calculated thanks to an
optimization method involving a target lens that has a virtual
optical function according to a wearer's prescription.
All embodiments previously recited and directed to multifocal
ophthalmic lenses according to the present invention can be
calculated thanks to preceding method for calculating.
The calculation step can be performed by using a ray-tracing method
or optimization algorithms. These methods are known by the one
skilled in the art, for example in the publication "Application of
optimization in computer-aided ophthalmic lens design" (P. Allione,
F. Ahsbahs and G. Le Saux, in SPIE Vol. 3737, EUROPTO Conference on
Design and Engineering of Optical Systems, Berlin, May 1999), which
is incorporated by reference in the present document.
Calculating the optical system of a lens with a given front face is
also known from the man skilled in the art and an example of an
accurate method is disclosed in patent document WO 2007/017766.
In the context of the present invention, the expression "wearer's
prescription" means a set of optical characteristics of optical
power, of astigmatism and, where relevant, of addition, determined
by an ophthalmologist or an eye care practitioner (ECR) in order to
correct the vision defects of an individual, for example by means
of a lens positioned in front of his eye. The term `astigmatism` is
used to denote the data pair formed by an amplitude value and a
value of angle. Although this is an abuse of language, it is also
sometimes used to denote the amplitude of the astigmatism only. The
context allows those skilled in the art to understand which usage
of the term is intended. Generally speaking, the prescription data
for a progressive spectacle lens comprise values of optical power
and of astigmatism at the distance-vision point and a dioptric add
power.
BRIEF DESCRIPTION OF THE DRAWINGS
Examples will now be described with reference to the accompanying
drawings wherein:
FIGS. 1a and 1b are sketches of an eye of a wearer and of an
ophthalmic spectacle lens capable of correcting the wearer's
ophthalmic vision and comprising a light guide optical element
arranged to output a supplementary image.
FIGS. 2 to 7 are sketches of embodiments of multifocal ophthalmic
spectacle lens according to the present invention.
Elements in the figures are illustrated for simplicity and clarity
and have not necessarily been drawn to scale. For example, the
dimensions of some of the elements in the figure may be exaggerated
relative to other elements to help improve the understanding of the
embodiments of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIGS. 1a and 1b are sketches that illustrate the principle of a
spectacle lens 10 which provides both an ophthalmic vision OV and a
supplementary vision by outputting a supplementary image SI to an
eye 100 of a wearer. The spectacle lens is capable of correcting a
wearer's ophthalmic vision; it has a back surface BS and a front
surface FS where the back surface is positioned closest to the
wearer's eye when the spectacle lens is worn; said spectacle lens
also comprises a light guide optical element 2 arranged to output a
supplementary image SI to the wearer through an exit surface ES of
said light guide optical element.
The lens 10 consists of at least two transparent and refringent
materials, which may be any organic or mineral material used in the
ophthalmic field. The light guide optical element 2 is inserted
between the back surface BS and the front surface FS. The light
guide optical element 2 has two opposite faces named "proximal
surface" PS and "distal surface" DS where the proximal surface is
closer to the eye of the wearer than the distal surface when the
spectacle lens is worn. Accordingly the proximal surface PS is the
surface of the light guide optical element which is the closest
from the back surface BS and the distal surface DS the surface of
the light guide optical element which is the closest from the front
surface FS.
According to an embodiment the proximal surface PS and the distal
surface DS are parallel surfaces;
According to another embodiment the proximal surface PS and the
distal surface DS are non-parallel surfaces;
According to an embodiment the proximal surface PS and/or the
distal surface DS is a (are) plane surface(s);
According to an embodiment the proximal surface PS and/or the
distal surface DS is a (are) curved surface(s); such a curved
surface is for example a spherical surface, a toric surface, a
sphero-toric surface; such a curved surface can also be an
aspherized spherical or toric or sphero-toric surface.
A first transparent and refringent material is situated around the
light guide optical element 2; the light guide optical element 2 is
made of a second transparent and refringent material; the
refractive indexes of said two materials may be identical, slightly
different or significantly different.
According to the present embodiment, the lens 10 has a convex front
surface FS and a concave back surface BS. The surfaces FS and BS
have respective curvatures which together determine, with the
value(s) of light refractive index(es) of the material(s) between
said two surfaces, an optical power of the spectacle lens, for the
ophthalmic vision OV.
In the frame of the present invention, this optical power varies
between the directions of sight so as to provide a multifocal
vision.
The light guide optical element 2 is appropriate for bringing
supplementary light from a source 3 which is not represented in
detail so as to produce a supplementary image SI. The structure of
the light guide optical element 2 is not the subject of this
description, and reference can be made to other documents available
on this subject. One example of a suitable light optical element is
described in patent document WO2005024491 or in patent document
WO200195027 in the name of the LUMUS Company. Generally, this
invention can apply to any light optical element embedded in the
lens providing supplementary image, for which the supplementary
image may be distorted or modified by the optical properties of the
back surface BS of the lens.
The lens 10 has a front portion 13 which is between the light guide
optical element 2 and the front surface FS, and a rear portion 12
which is between the light guide optical element 2 and the back
surface BS.
The light guide optical element 2 is limited transversely within an
area of the lens 10 in certain directions approximately parallel to
the faces FS and BS. In such a configuration, the front portion 13
and the rear portion 12 of the lens 10 extend beyond a peripheral
edge 2e of the light guide optical element 2. The lens 10 then has
an intermediate portion 11 which extends beyond the edge 2e of the
light guide optical element 2 and which continually links the
portions 13 and 12 to a peripheral edge E of the lens 10.
The light guide optical element 2 is virtually divided in two zones
2a and 2b separated by a virtual edge 2e'. Zone 2a is the imaging
part wherefrom does the supplementary image come from according to
the eye of the wearer; zone 2b is a propagation part wherein the
supplementary image is propagated from the source 3 without
supplying an image to the wearer.
The edge of zone 2a is the contour of the supplementary image
output by the light guide optical element; said supplementary image
intercepts the proximal surface PS according to an exit surface ES.
One names "opposite surface" OS the surface corresponding to the
exit surface ES on the distal surface. According to the present
example the imaging part is substantially a rectangle whose width
is W and whose height is H.
According to a commonly used optical referential, the exit surface
ES is defined by an angular aperture contour, denoted
AC(.alpha.,.beta.), .alpha. being the eye declination angle and
.beta. being the eye azimuth angle. .alpha., .beta. pole is the
center of rotation, CRE, of the eye 100 of the wearer behind the
lens. 101 corresponds to the axis where .alpha.=.beta.=0.
According to an example, the aperture AC may be +/-15.degree.
(degree) either side of an optical axis of the supplementary
vision, which passes through the center of the exit surface ES.
Said aperture is defined in the azimuthal plane by
|.beta..sub.1|+|.beta..sub.2|. It is defined in the perpendicular
plane by |.alpha..sub.1|+|.alpha..sub.2|. In said embodiment, the
.beta. variation range within AC(.alpha.,.beta.) is about
30.degree.. In said embodiment, the .alpha. variation range within
AC(.alpha.,.beta.) is about 15.degree..
The generatrix lines of the limit of the angular aperture contour
intersect the back surface BS of the lens in an area in which the
two visions, ophthalmic and supplementary, are superposed. In the
configuration of FIGS. 1a and 1b, the respective optical axes of
the ophthalmic vision and of the supplementary vision are one and
the same, but they may be distinct.
FIGS. 1a and 1b represent the spectacle lens in the position of use
by the wearer. The eye of the wearer 100 is therefore situated
behind the lens 10 on the side of the back surface so that it
receives, on the one hand, light OV originating from the
environment which is situated in front of the lens, and, on the
other hand, the light corresponding to the supplementary image SI
which is brought by the light guide optical element 2. The light
beams of the two lights OV and SI correspond respectively to the
ophthalmic vision and to a supplementary vision. They respectively
form, after having passed through the pupil 120, an ophthalmic
image and a supplementary image on the retina 110 of the wearer.
The reference 130 designates the iris of the wearer which surrounds
his pupil 120. The direction in which the wearer is looking
corresponds to the optical axis of the eye 100. It intersects the
surfaces FS and BS of the spectacle lens at respective points which
vary when the eye 100 turns in the orbit of the wearer.
Given that the light OV passes through the two surfaces FS and BS
of the lens, they both contribute to optical characteristics of the
lens which are relative to the ophthalmic vision. However, the
light SI does not pass through the surface FS, so that this surface
does not contribute to optical characteristics of the lens which
are relative to the supplementary vision. Because of this
difference between the lights OV and SI, they do not present
convergence characteristics which are identical after they have
passed through the back surface BS of the lens. For this reason,
the ophthalmic and additional images which are formed on the retina
may not be simultaneously clear.
The expression "optical characteristics of lens which are relative
to one or other of the ophthalmic and supplementary visions" should
be understood notably to mean an optical power value, astigmatism
values, optical distortion values, etc., of the lens for each
direction in which the wearer looks.
Following examples (examples 1 to 9) are given to illustrate
embodiments where an ophthalmic spectacle lens capable of
correcting the wearer's ophthalmic vision and comprising a light
guide optical element arranged to output a supplementary image
according to FIGS. 1a and 1b is designed to fulfill the
requirements of the present invention.
According to said embodiments the proximal surface PS and the
distal surface DS are parallel surfaces.
According to said embodiments the proximal surface PS and the
distal surface DS are plane surfaces. According to other possible
embodiments, the proximal surface PS and the distal surface DS are
curved surfaces.
EXAMPLE 1
Progressive Addition Spectacle Lens where the Back Surface BS is a
Progressive Surface and where the Angular Aperture Contour
AC(.alpha.,.beta.) is Located in the Far Vision Zone
Example 1 is illustrated by FIG. 2.
FIG. 2 is a cut of said lens according to .beta.=0.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens comprising a far vision zone 21, an
intermediate vision zone and a near vision zone (in this case: 22)
or a progressive addition spectacle lens comprising a far vision
zone 21 and an intermediate vision zone (in this case: 22).
The front surface FS is chosen within the list consisting of a
spherical surface, a toric surface, a sphero-toric surface. The
front surface FS can also be an aspherized spherical or toric or
sphero-toric surface.
The back surface BS is a progressive surface.
The angular aperture contour AC(.alpha.,.beta.) is located in the
far vision zone 21.
The inventors have determined that such a zone is both an area of
stabilized optical power and an area of stabilized astigmatism.
In said zone, the optical device OD formed by the exit surface ES,
the back surface BS and the optical material located between said
exit surface ES and said back surface BS fulfills the requirement
of equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD also fulfills the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
EXAMPLE 2
Progressive Addition Spectacle Lens where the Back Surface BS is a
Progressive Surface or a Regressive Surface and where the Angular
Aperture Contour AC(.alpha.,.beta.) is Located in the Far Vision
Zone
Example 2 is illustrated by FIG. 3.
FIG. 3 is a cut of said lens according to .beta.=0.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens comprising a far vision zone 21, an
intermediate vision zone and a near vision zone or a progressive
addition spectacle lens comprising a far vision zone 21 and an
intermediate vision zone.
The front surface FS is chosen within the list consisting of a
regressive surface and a progressive surface.
The back surface BS is a progressive surface or a regressive
surface.
The angular aperture contour AC(.alpha.,.beta.) is located in the
far vision zone 21.
The inventors have determined that such a zone is both an area of
stabilized optical power and an area of stabilized astigmatism.
In said zone, the optical device OD formed by the exit surface ES,
the back surface BS and the optical material located between said
exit surface ES and said back surface BS fulfills the requirement
of equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD also fulfills the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
EXAMPLE 3
Progressive Addition Spectacle Lens where the Back Surface BS is a
Progressive Surface or a Regressive Surface and where the Angular
Aperture Contour AC(.alpha.,.beta.) is Located in the Near Vision
Zone
Example 3 is not represented.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens comprising a far vision zone, an
intermediate vision zone and a near vision zone or a progressive
addition spectacle lens comprising an intermediate vision zone and
a near vision zone.
The back surface BS is a progressive surface or a regressive
surface.
The front surface FS can be chosen within the list consisting of a
spherical surface, a toric surface, a sphero-toric surface. The
front surface FS can also be an aspherized spherical or toric or
sphero-toric surface.
The front surface FS can also be chosen within the list consisting
of a regressive surface and a progressive surface.
The angular aperture contour AC(.alpha.,.beta.) is located in the
near vision zone.
The inventors have determined that such a zone is both an area of
stabilized optical power and an area of stabilized astigmatism.
In said zone, the optical device OD formed by the exit surface ES,
the back surface BS and the optical material located between said
exit surface ES and said back surface BS fulfills the requirement
of equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD also fulfills the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
EXAMPLE 4
Progressive Addition Spectacle Lens where the Back Surface BS is a
Progressive Surface or a Regressive Surface and where the Angular
Aperture Contour AC(.alpha.,.beta.) is Located in a Zone where
.alpha.Meets the Intermediate Vision Zone
Example 4 is illustrated by FIGS. 4a and 4b.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens chosen within the list consisting of a
spectacle lens comprising a far vision zone, an intermediate vision
zone and a near vision zone; a spectacle lens comprising an
intermediate vision zone and a near vision zone; a spectacle lens
comprising a far vision zone and an intermediate vision zone.
The back surface BS is a progressive surface or a regressive
surface.
FIG. 4a is a schematic view of the back surface BS that represents
iso sphere curves 42 of said back surface BS. The sphere value
difference between two neighbouring iso sphere curves is 0.5
Diopter.
FIG. 4b is a schematic view of the back surface BS that represents
iso astigmatism curves 43 of said back surface BS. The astigmatism
difference between two neighbouring iso astigmatism curves is 0.5
Diopter.
The front surface FS can be chosen within the list consisting of a
spherical surface, a toric surface, a sphero-toric surface. The
front surface FS can also be an aspherized spherical or toric or
sphero-toric surface.
The front surface FS can also be chosen within the list consisting
of a regressive surface and a progressive surface.
The angular aperture contour AC(.alpha.,.beta.) is located in the
temporal zone or in the nasal zone of the spectacle lens, in a zone
where a meets the intermediate vision zone.
The inventors have determined that such a zone 41 may be both an
area of stabilized optical power and an area of stabilized
astigmatism.
In said zone, the optical device OD formed by the exit surface ES,
the back surface BS and the optical material located between said
exit surface ES and said back surface BS fulfills the requirement
of equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD also fulfills the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
EXAMPLE 5
Progressive Addition Spectacle Lens where the Back Surface BS is a
Progressive Surface or a Regressive Surface Comprising a Surface
Discontinuity Located Around the Angular Aperture Contour
AC(.alpha.,.beta.)
Example 5 is illustrated by FIG. 5.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens chosen within the list consisting of a
spectacle lens comprising a far vision zone, an intermediate vision
zone and a near vision zone; a spectacle lens comprising an
intermediate vision zone and a near vision zone; a spectacle lens
comprising a far vision zone and an intermediate vision zone.
FIG. 5 is a schematic view of the back surface BS that represents
iso astigmatism curves 53 of said back surface BS. The astigmatism
difference between two neighbouring iso astigmatism curves is 0.5
Diopter.
Zone 52 is a surface discontinuity located around the angular
aperture contour AC(.alpha.,.beta.) 51. According to said
embodiment, the surface within zone 52 is a sphero-toric surface
where the surface is a progressive or a regressive surface out of
zone 52.
Said zone 51 is designed so as the optical device OD formed by the
exit surface ES, the back surface BS and the optical material
located between said exit surface ES and said back surface BS
fulfills the requirement of equation (E1) when (.alpha.,.beta.) is
within the contour AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD can also fulfill the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
Such a surface discontinuity in zone 51 may be obtained when
designing the back surface BS of the progressive addition spectacle
lens; it can also be obtained by machining the back surface BS of a
progressive addition spectacle lens.
EXAMPLE 6
Progressive Addition Spectacle Lens where the Front Surface FS is a
Progressive Surface and the Back Surface BS is a Surface where the
Absolute Values of the Mean Sphere Value Differences Over Said
Surface are Equal or Less to 0.5 Diopter
Example 6 is illustrated by FIG. 6.
FIG. 6 is a cut of said lens according to .beta.=0.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens chosen within the list consisting of a
spectacle lens comprising a far vision zone, an intermediate vision
zone and a near vision zone; a spectacle lens comprising an
intermediate vision zone and a near vision zone; a spectacle lens
comprising a far vision zone and an intermediate vision zone.
The back surface BS can be chosen within the list consisting of a
spherical surface, a toric surface, a sphero-toric surface.
Accordingly, the absolute values of the mean sphere value
differences over said whole back surface are equal or less to 0.5
Diopter.
The back surface BS can also be an aspherized spherical or toric or
sphero-toric surface where the absolute values of the mean sphere
value differences over said surface are equal or less to 0.5
Diopter all over said back surface.
The back surface BS can also be chosen within the list consisting
of a regressive surface and a progressive surface where the
dioptric add power is equal or less to 0.5 Diopter.
The inventors have determined that such a back surface BS is an
area of stabilized optical power suitable to form an optical device
OD with an exit surface ES.
All over said back surface BS, the optical device OD formed by the
exit surface ES, the back surface BS and the optical material
located between said exit surface ES and said back surface BS
fulfills the requirement of equation (E1) when (.alpha.,.beta.) is
within the contour AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD can also fulfill the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
Accordingly, the exit surface can be placed in several zones of the
back surface BS, such as illustrated as ES, ES', ES'' when one or
several of light guide optical element 2, 2', 2'' are inserted
within the front surface FS and the back surface BS.
According to different or combined examples, ES is located in a far
vision zone, ES' is located in an intermediate vision zone, ES'' is
located in a near vision zone.
EXAMPLE 7
Progressive Addition Spectacle Lens where the Back Surface BS is a
Progressive Surface or a Regressive Surface, and where the Angular
Aperture Contour, AC(.alpha.,.beta.), is Located in a Part of the
Intermediate Vision Zone where the Absolute Value of the Mean
Sphere Value Differences Over Said Part of the Intermediate Vision
Zone are Equal or Less to 0.5 Diopter
Example 7 is illustrated by FIG. 7.
FIG. 7 is a cut of said lens according to .beta.=0.
The multifocal ophthalmic spectacle lens 10 is a progressive
addition spectacle lens chosen within the list consisting of a
spectacle lens comprising a far vision zone, an intermediate vision
zone and a near vision zone; a spectacle lens comprising an
intermediate vision zone and a near vision zone; a spectacle lens
comprising a far vision zone and an intermediate vision zone.
The front surface FS can be chosen within the list consisting of a
spherical surface, a toric surface, a sphero-toric surface. The
front surface FS can also be an aspherized spherical or toric or
sphero-toric surface.
The front surface FS can also be chosen within the list consisting
of a regressive surface and a progressive surface.
The back surface BS is a progressive surface or a regressive
surface. The angular aperture contour, AC(.alpha.,.beta.), is
located in a part of the intermediate vision zone where the
absolute value of the mean sphere value differences over said part
of the intermediate vision zone are equal or less to 0.5
Diopter.
Such a result can be obtained when designing the back surface BS
and the front surface FS of the progressive addition spectacle
lens.
According to an embodiment designing the back surface BS and the
front surface FS uses firstly an initial back surface BS which is a
progressive surface or a regressive surface with a standard design
72 (dotted line) in the intermediate vision zone and also all over
the back surface; the combination of the initial back surface BS
and of an initial front surface FS defines an initial optical
system of an initial progressive lens. The initial design of the
initial back surface BS is modified and a final progressive surface
or regressive surface 71 in the intermediate vision zone is
calculated which is a complex surface. Said complex surface
calculated so that the optical device OD formed by the exit surface
ES, the final back surface BS and the optical material located
between said exit surface ES and said final back surface BS
fulfills the requirement of equation (E1) when (.alpha.,.beta.) is
within the contour AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
The optical device OD can also fulfill the requirement of following
equation (E2) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
The initial front surface in the intermediate vision zone 74
(dotted line) is then modified and a final front surface in the
intermediate vision zone 73 is calculated so that the final optical
system, which is the combination of the final back surface BS and
of the final front surface FS, defines a final optical system of
the progressive lens which is substantially identical to the
optical system of the initial progressive lens.
Here above examples demonstrate that the present invention is
advantageous in the case of a progressive lens, for example when
the rear surface presents power and or astigmatism variations.
One example of such lens is a "Full Back Side" progressive lens
where the front surface is a spherical surface and the rear surface
is a progressive surface. In this case the rear surface presents
power and astigmatism variations. If these variations occur on the
optical path of the supplementary image, they will cause
aberrations and lead to a blurry supplementary image. In order to
provide a supplementary image with good acuity to the wearer, it is
useful to design the lens according to the present invention so
that the power variations and the astigmatism variations are
limited within the contour AC(.alpha.,.beta.).
Another example is a "Dual Side" progressive lens where both the
front surface and the rear surface are progressive surfaces. In
this case also, the rear surface presents power and astigmatism
variations. The same preceding argument applies.
EXAMPLE 8
Bifocal Ophthalmic Spectacle Lens
Example 8 is not represented.
According to said example, the multifocal ophthalmic spectacle lens
is a bifocal lens wherein the optical device OD comprises an area
of stabilized optical power and where the angular aperture contour
AC(.alpha.,.beta.) is situated in the area of stabilized optical
power so that the optical device (OD) fulfils the requirement of
following equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
According to a further embodiment, the multifocal ophthalmic
spectacle lens is a bifocal lens wherein the optical device OD also
comprises an area of stabilized astigmatism and where the angular
aperture contour AC(.alpha.,.beta.) is situated in the area of
stabilized astigmatism so that the optical device (OD) fulfils the
requirement of following equation (E2) when (.alpha.,.beta.) is
within the contour AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
EXAMPLE 9
Trifocal Ophthalmic Spectacle Lens
Example 9 is not represented.
According to said example, the multifocal ophthalmic spectacle lens
is a trifocal lens wherein the optical device OD comprises an area
of stabilized optical power and where the angular aperture contour
AC(.alpha.,.beta.) is situated in the area of stabilized optical
power so that the optical device (OD) fulfils the requirement of
following equation (E1) when (.alpha.,.beta.) is within the contour
AC(.alpha.,.beta.): -0.5
Diopter.ltoreq.P(.alpha.,.beta.)-P.sub.mean.ltoreq.0.5 Diopter;
(E1):
According to a further embodiment, the multifocal ophthalmic
spectacle lens is a trifocal lens wherein the optical device OD
also comprises an area of stabilized astigmatism and where the
angular aperture contour AC(.alpha.,.beta.) is situated in the area
of stabilized astigmatism so that the optical device (OD) fulfils
the requirement of following equation (E2) when (.alpha.,.beta.) is
within the contour AC(.alpha.,.beta.): 0
Diopter.ltoreq.UnAsti(.alpha.,.beta.).ltoreq.0.5 Diopter. (E2):
The invention has been described above with the aid of embodiments
without limitation of the general inventive concept; in particular
the parameters are not limited to the examples discussed.
* * * * *